In an apparent move to clear stock ahead of a next-generation model introduction, U.S. retailers Best Buy and Walmart have been running interesting promotions for some time now, offering deep discounts on iPhone sales and attractive device trade-ins.

As for the iPhone 5, both companies have long offered Apple’s flagship handset with a two-year contract with U.S. carriers AT&T, Verizon and Sprint. And this past weekend, each has added a prepaid iPhone 5 option on T-Mobile to its roster…

As observed by TMoNews, these offers are good for any of T-Mobile’s current prepaid plans and the retailers will also activate your device in-house.

Walmart, which started selling a T-Mobile iPhone 5 this past Friday, undercuts (above) Best Buy’s asking price (below) of $649 by $20. For instance, Walmart will happily sell you a prepaid iPhone 5 on T-Mobile for $629. By comparison, the online Apple Store charges $649 for the device, same as Best Buy.

Walmart also offers in-store financing plans separate from T-Mobile’s Simple Choice equipment installment plans. About 1300 Walmart locations are said to be currently selling the device in both black and white, allegedly in the 16GB variety only.

If you’re in the market for an iPhone 5, are a fan of prepaid and are too lazy to find a T-Mobile store, you now have an additional option to buy a T-Mobile device at your nearest Walmart or Best Buy outlet.

In related T-Mobile news, the carrier on Friday said it will pay $308 million in cash to acquire AWS spectrum from U.S. Cellular in order to expand its 4G LTE to 29 key markets in the Mississippi Valley region.

The Deutsche Telekom-owned telco also sent out invites (above) for a July 10 media event teasing its “boldest moves yet,” likely concerning new devices and mobile tarrifs.

We heard whispers the event will offer details on T-Mobile’s Phase 2 Uncarrier strategy, specifically the introduction of a new Simple Choice with no credit check rate plan.